RU1783314C - Balance - Google Patents

Abstract

.Use: weighing technique, continuous weighing of bulk materials with belt conveyors. The inventive balance contains 1 belt conveyor (1-3), 1 speed sensor (4), 1 weight sensor (5), 1 analog-to-frequency converter (6), 1 optical signal isolation unit (7), 2 elements 2 I-2 OR-NOT (8), 1 toggle switch for operating mode control (9), 3 counters (10,12, 15), 1 toggle switch for setting the control duration of the measuring section (11), 2 one-shots (13, 16), 1 toggle switch for setting the number of measuring sections (14), 1 key control panel (17). 1 toggle switch for setting the type of work (18), 1 microprocessor computing device (19), 1 timer unit (20), 1 display unit (21), 1 toggle switch for setting the print interval (22), 1 block for generating print intervals (23) , 1 printing device (24). 1-2-3-4-7-8-19-20-21, 5-6-7, 8-9-15, 9-10-19,11-12-13,12-8,14-15- 16.17-19.18-19. 19-6, 20-19. 20-23. 23-19, 22-24-24, 19-24. 1 ill. se 1L C

Description

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The invention relates to a weighing technique and can be used for continuous weighing of bulk materials transported by belt conveyors in the mining, metallurgical, construction and other industries.

A device for determining the performance of a conveyor belt is known. However, due to the possibility of increasing the length of the measured sections of the conveyor belt (loss of marks during operation and the impossibility of their urgent replacement in a continuous technological cycle), such a device does not provide the required weighing accuracy. This is due to the final capacity of the counter for the number of measured sections of the conveyor belt and the counter for measuring the passage time of the measured section.

The closest in technical essence to the present invention are conveyor scales. The implementation of such conveyor scales allows the control of hardware and software without the use of reference equipment on certification days when the equipment is switched to control mode, but does not guarantee the reliability of previously obtained weighing results during calibration periods and requires a separate check of the weight sensor, since over time there is a change numerical values of the output signal. Due to the aging of the sensor, as a rule, the starting point of the weight sensor signal (10% Pnom) leaves, as well as the entire characteristic is shifted towards increasing or decreasing the output signal at the same load values. Since the values of the weight of the cargo on the conveyor belt are summed over time, such changes can lead to significant temporary errors, which are observed with temperature changes and the long-term (more than 1 year) operation of the weight sensors.

The purpose of the invention is to increase the accuracy of weighing and reliability of measurements by automatically controlling the reference signal proportional to the signal of the measuring channel at predetermined time intervals directly by the microprocessor computing device itself, in operating mode, and also to increase the reliability of the equipment due to simplification of its implementation scheme. Comparison of the claimed solution with other technical solutions of this class shows that the previously listed blocks and elements of devices in electronic,

microprocessor and computer technology are known, however, their introduction into the indicated connection with other elements and blocks into the inventive device exhibits new properties in the aggregate. This leads to increased accuracy and reliability of weighing on the conveyor belt when performing automatic control of the measuring channel in the working

0 mode.

The drawing provides a functional diagram.

The balance contains a conveyor 1, on the belt of which metal buttons (tags) 2 are installed at regular intervals 2. and the belt of the conveyor rests on the roller bearings 3 of the conveyor, on which the speed sensor 4 and the load receiving unit with a strain gauge weight sensor 5 connected to the analogue are mounted -frequency converter 6, the outputs of which, like the speed sensor 4 are connected to the optical signal isolation unit 7, the outputs of which are connected to the first inputs of two elements

5 2 AND-2 OR NOT 8, the second inputs of which are connected to the first and fourth outputs of the toggle switches 9 for controlling operation modes. At the third and fourth inputs of the first element 2I-2OR-NOT, and the third input of the second

0 element 2I-2OR OR NOT connected also the outputs of the control toggle switches 9 to the inputs of which are connected the five outputs of the binary counter 10. Toggle switches 11 to set the control duration of the measurement

5 sections are connected with their output bus to the information inputs of the binary counter 12, the transfer output of which is connected to the fourth input of the second logic element 2I-2OR-NOT 8 and to the input of the single-oscillator 13, the output of which is connected to the control input of the binary counter 12. The outputs of the toggle switches 14, the number of measuring sections is connected to the information inputs of the binary counter 5 ka 15, to the subtracting input of which the output of the second logical element 2I-2OR-NOT is connected, and the transfer output is connected to the input of the single-shot 16, Exit is fed to the control input of the counter 15.

0 Keyboard control 17 of its output bus, as well as the switches 18 setting the type of work with three output communications connected to the input of the microprocessor computing device 19. To the inputs

5 of this device also connects the outputs of the first and second logic elements 2I-2 OR-NOT 8 and the transfer output of the binary counter 15, and its three outputs are connected to the control inputs of the analog-to-frequency converter 6. The timer unit 20 is connected via the information bus and two communications to the microprocessor computing device 19, as well as to the inputs of the display unit 21 of the current time. The toggle switch 22 for setting the print interval of the measurement results is connected via a bus to the input of the print interval generating unit 23, to one of the inputs of which a timer unit 20 is connected via communication, one of the outputs of which, in turn, is connected to the counting input of the first binary counter 10, and the second to the subtracting input of the binary counter 12. The unit for generating printing intervals 23 is connected to the printing device 24 by two connections, and three connections to the input of the microprocessor computing device 19, information and the tire of which is connected to the input of the printing device 24. The load receiving unit with a strain gauge of weight 5 is made using one roller support and is built in between the guide frames of the conveyor belt. The roller support of the load receiving platform is installed at a distance of I from two adjacent support rollers of the stav. Determining the value of I allows you to mark the entire conveyor belt into measuring sections and install metal buttons or staples on the tape. A speed sensor 4 is installed under the conveyor belt to generate signals of a given duration corresponding to the beginning of passage of the measuring section. A strain gauge weight sensor 5 with an analog output is connected to the input of the analog-to-frequency converter, to the input of which three control links are also connected from the output of the microprocessor computing device 19. Using these control links, the sensor signal is disconnected at specified times weights and connection to the input of an exemplary reference signal. This signal is converted to frequency and measured by a microprocessor computing device. The values of the reference signals correspond to 10, 50 and 90 percent of the rated load of the weight sensor. The operation of the two logic elements 2I-2 OR-NOT 8 is controlled by the toggle switches 9 for controlling the operating modes of the scales. Depending on the output signals of the toggle switches 9, the input of the microprocessor computing device 19 and the binary counter 15 can be connected a) in the operating mode, a weight sensor and a speed sensor; b) in the calibration mode of the weight sensor and speed sensor, or weight sensor and a reference counter 12

the length of the computing device is connected to the outputs of the toggle switch of the setup of the measurement type, the first timer output is connected to the fourth input 5 of the microprocessor computing device, the second bus of which is connected to the first bus of the timer, the second bus of which is connected to the display unit, the second timer output is connected to the first input

0 of the unit for generating printing intervals, the other inputs of which are connected to the outputs of the toggle switch set for setting the intervals of printing, the three outputs of the unit for generating intervals of printing are respectively connected5 to the control inputs of the microprocessor computing device, to the output bus of which a printing device is connected, to the control inputs of which are connected the sixth and sixth

0 outputs of the unit for generating printing intervals, and the timer input is connected to the output of the microprocessor computing device and a toggle switch for controlling the operation mode, characterized in that, with

5 in order to increase the accuracy of weighing, they introduced a third counter and two 2I-2OR-NOT elements, the first inputs of which are respectively connected to the first, second output of the optical signal isolation unit, the second, third and fourth inputs of the first 2I-2OR-NOT connected with three outputs of the toggle switch for operating mode control, the second, third inputs of the second element 2I-2OR-HP

5, respectively, are connected to the fourth and fifth outputs of the toggle switch for operating mode control, the inputs of which are connected to the outputs of the third counter, the counting input of which is connected to the third

0 by the timer output, the fourth output of which is connected to the subtracting input of the first counter, the transfer output of which is connected to the fourth input of the second element 2I-2OR-NOT, the output of which is connected to the subtracting input of the measuring sections; c) in calibration mode with checking the equipment, a simulator of the frequency of the weight sensor. The frequency of the quartz oscillator of the timer unit 20 goes to the counting input of counter 10. At the output, we get its division by 2, 4, 8, 16 and 32. The toggle switches 11 of the installation simulating the duration of the measuring section of the conveyor belt are connected to the information inputs of the binary counter

5 12 which works in the subtraction mode. The initial state of the counter triggers is single, which makes it possible to develop a voltage drop of short duration if it is zeroed and reset to the initial state at the loan output (transfer).

connect the outputs of the toggle switches in the reverse code to the information inputs of the counter, then the required time delay will be typed in the direct code corresponding to the required time delay. When a signal is generated at the transfer output (loan) of the meter, a single-shot 13 is triggered and will enter the required code at the control input with its output signal. Binary counter 15 is designed to individualize the balance depending on the length of the conveyor belt. The source code corresponding to the number of measuring sections is entered from the toggle dial 14 similar to the previously described method of entering information into the counter 12, the unit for generating printing intervals 23 is used to set the necessary printing intervals for the measurement results. Using the toggle switches 22, you can set the printing time: 1) continuous printing; 2) print after 1 min .; 3) print after 6 minutes and subsequently with an interval of 5 minutes, starting at 10 minutes. Toggle switches 18 for setting the type of work allow to carry out: a) starting the program (balance) in the mode of receiving signals arriving at the input of a microprocessor computing device; b) start the calibration program and the weighing program after completing the calibration mode; c) set automatic control of the measuring channel in the operating mode at a print time equal to or more than b minutes.

Scales work as follows. There are two modes of operation of the equipment: control of the hardware and software, and, in fact, the operation of the equipment for its intended purpose.

Consider the operation of the balance in control mode during calibration. Using the toggle switches, by operating modes, we give the resolving potential to the fourth input of the first logical element 2I-2 OR-NOT, as well as to the third input of the second logical element 2I-2 OR-NOT. When applying enable potentials to the specified inputs of the logic elements at the second inputs of the first and second logic elements 2I-2OR-NOT will be inhibitory potential. This will lead to the fact that one of the outputs of the first binary counter 10 will be connected to the output of the first logic element 2I-2 OR- NOT using the toggle switches of set 9 of the frequency switch, for example, the low frequency itself will be connected, simulating the load on the weight sensor from an empty conveyor belt . The output of the binary counter 12 transfer simulating the time (speed) of the transition of the measuring sections will be connected to the output of the second logic element 2I-2IL INE. By setting the dials of the 18 v set

starting position and calibration, as well as the dial switch 22 to the continuous printing position, after the signal at the counter transfer output 15 of the number of measuring sections of the conveyor belt starts, the microprocessor computing device 19 starts to work, since the specified signal corresponds to the conditional point of the tape start. After starting the program microprocessor computing device 5 measures the frequency coming from the output of the first logic element 2I-2OR-NOT. Frequency measurement by the timer of microprocessor computing device 19 continues

0 time interval defined by the pulses coming from the output of the second logic element 2I-21 / 1LI-NOT. The same pulses are fed to the subtracting input of the counter 15. The interval of the pulse input 5 is determined by the counter 10 with the toggle switch 11. During the same period of time, the corresponding input to the second input of the microprocessor-based computing device is received from the timer unit 20

0 frequency, as a reference frequency for determining the measurement interval. In the continuous printing mode, when calibrating the equipment with reference signals, the following are printed: a) the reference frequency simulating a weight sensor; b) the reference frequency corresponding to the measurement interval. For a given number of measuring sections, the previously indicated values will be printed the corresponding number of times, and then, on the instructions of the microprocessor computing device, the average value of the measured frequency will be printed, simulating the load of the weight sensor and the average frequency value.

5 corresponding to the travel time of the measuring sections. When printing average measurement values using the toggle switch 9, we set a higher frequency, that is, the frequency corresponding to

0 10% of the nominal load of the conveyor. Using the dials of set 18, we set the type of work - weighing, and the dials of set 22 - print mode 1 minute. If previously the control, the print potential passed through the first communication line to the microprocessor-based computing device, then in the print mode 1 minute it is installed on the second communication line from the print interval selection unit 23. In the continuous printing mode, the printing device has been

is turned on, and in the interval printing mode, the print interval generating unit 23 turns on the printing device at a predetermined interval. When the printer is turned on, the signal from the initial setting of the printing registers to the initial state is supplied from the block 23. After 1 min, the microprocessor-based computing device outputs to the printing device the measurement value obtained by the calculation formula

Ohm Ј ((FAi-F0i) () KAKv), (2.1)

i 1

where QM is the weight of the cargo passed on the conveyor belt in one minute of measurement, kg;

FI is the frequency of the weight sensor corresponding to the ith measuring section during calibration, Hz;

Rd | - frequency of the weight sensor, corresponding to the 1st measuring section in the weighing mode, Hz;

Fvoi is the frequency of the timer block corresponding to the time taken by the measuring section during calibration, Hz; Fvi is the frequency of the timer block corresponding to the time taken by the measuring section during weighing, Hz;

Cd is the frequency to weight conversion coefficient. kg / Hz;

Kv is the frequency conversion coefficient corresponding to the passage time of the conveyor belt, s / Hz;

i - the second measuring section;

m is the number of measurement sections that have passed during the measurement. Since the measurement sections did not change during calibration — checking the equipment of the scales, the difference in frequencies corresponding to the passage time of the sections is zero, and therefore, the unit value will be used in the calculation formula. Therefore, the value of the print value will be known, since it coincides with the calculated value, which allows us to judge the operation of the hardware and software of the scales. In the operating mode, depending on the change in the speed of passage of the measuring sections, the frequency difference corresponding to these sections can change, and therefore, a correction coefficient is calculated to calculate the integral productivity. When printing results at specified intervals, the print time (hours and minutes) and the value are printed integrated rise performance. By changing the frequency value using the tumbler dial 9, after the next printing, it is possible to control the operation of the balance at maximum load

on the weight sensor. The control weighing mode after preliminary calibration allows you to monitor and configure all the main components of the balance except the optocoupler isolation unit and the analog-to-frequency converter unit. For the purpose of a control automatic comparative check of the characteristics of the weight sensor and the analog-to-frequency converter, the control output frequencies of which correspond to three control points of the analog output signal of the weight sensor, a relay unit and three reference sources are introduced into the circuit of the analog-to-frequency converter. The first reference signal in magnitude corresponds to the output of the weight sensor measured at 20% of the rated load, the second to 50% of the rated load and the third to 90% of the rated load of the used weight sensor. In the control weighing mode, with the help of the toggle switch set 9, we supply a control signal to the second input of the logic circuit 2I-2 OR-NOT, and using the toggle switches 18 we send the control signal of the measuring channel to the input of the microprocessor computing device 19, setting the print interval for the results using the toggle switch set 22 (equal to b minutes. In this control mode, after the next printing of the previous measurement, the microprocessor-based computing device 19 is connected via a link to an analog-frequency converter It gives the signal to the input of the relay node. The output of the weight sensor is disconnected from the input of the analog-to-frequency converter 6, and instead of the weight sensor, the first reference signal source is connected.

 19 within 6 minutes, it measures the output frequency of the analog-to-frequency converter 6, calculates according to the previously recorded expression, and the result is printed. In the next b minutes, the second reference source will be turned on and the measurement result and the measurement (print) time will be printed, and then the third. The measurements obtained make it possible to draw conclusions about the operation of the measuring channel, including the analog-to-frequency converter b and the optical interface unit 7. In operation, when calibrating using the control signals of the toggle switches 9, the weight sensor and the speed sensor of the conveyor belt are connected to the input of the microprocessor computing device 19 , In continuous printing mode, the values of the frequency of the weight sensor measured during the passage of the measuring section and the quartz frequency timer a is equal to the travel time of the site. The same values will be recorded in the memory of the microprocessor computing device. The empty tape calibration operation can be repeated several times. When switching to weighing mode (toggle switches 18) and printing with an interval equal to 1 minute, the integrated output will be printed, equal to the weight of the mass being moved by the conveyor belt, and the current time, initiated by the indication unit 21. If the conveyor belt is not loaded, then Zeros or the magnitude of the accumulated error due to the dynamics of the conveyor belt will be printed.

When the printing time is set to more than 6 minutes, the microprocessor-based computing device prints the integrated performance in ascending order for the measurement period, the current time of the day, and in pairs: a) the lowest value of the measured frequency of the weight sensor for a given interval and the frequency corresponding to the first reference source; b) the average value of the frequency of the weight sensor and the frequency of the second reference source; c) the highest frequency of the weight sensor and the frequency of the third reference source. All the indicated values are measured and printed out if there is an enable signal for automatic control of the measuring channel coming from the toggle switch 18. Based on the obtained frequency values, the operator or maintenance personnel can make a conclusion about the reliability of the results obtained and the operation of the hardware and software of the balance in the operating mode.

Claims (1)

SUMMARY OF THE INVENTION Scales containing a conveyor belt with a load-bearing unit and a weight sensor, the outputs of which are connected to the first input of an analog-to-frequency converter, the output of which is connected to the first input of the optical signal isolation unit, the second input of which is connected to a speed sensor, the outputs of the toggle switch sets of control duration measuring sections and their numbers are respectively connected to the information inputs of the first and second counters, to the transfer outputs of which respectively are connected the first the first and second single vibrators, a control panel is connected to the first bus of the microprocessor computing device, three information and control inputs of the microprocessor second counter and the fourth input of the microprocessor computing device, the fifth input of which is connected to the output of the first element 2I-2 OR-NOT, the sixth input - with the transfer output of the second counter, the three control outputs of the microprocessor computing device are respectively connected to the second, third and fourth inputs of the analog-frequency the forming, the outputs of the first, second monostable multivibrators are respectively connected with the control inputs of the first and second counters.